Lot, batch & COA requirements.
How PeptideSmart verifies suppliers. Required tests, additional tests we track, testing labs we recognize, and what every COA line item actually measures.
Must appear on every COA
- ✓Identification — Is it the right compound?
- ✓Net Content — Is the amount correct?
- ✓Net Purity — How clean is it?
Not required but rewarded
- ○Sterility — Microbial contamination check
- ○Endotoxins — Bacterial toxin levels
- ○Heavy Metals — Elemental contaminants
- ○Lot Traceability — Batch matching
- ○Third-Party Lab — Independent verification
- ○Conformity — Batch consistency
COA freshness requirements
- High-traffic listings: COAs must be approximately 6 months old or newer.
- Older batches: Require updated testing or clearance pricing.
- Policy effective: October 31, 2025
What each test measures
Educational overview. Methods and limits on your COA are defined by the issuing laboratory.
Identification testing
Is this actually what the label says?
Confirms the molecular identity of the peptide. Doesn't measure purity or quantity — answers ONE question: is this the correct compound?
In a mass spectrometer, the sample is ionized and fragmented. The instrument measures mass-to-charge ratios. The pattern is compared to the expected pattern for the labeled peptide. A match supports the sample is the claimed compound. A mismatch suggests mislabeling, substitution, or synthesis error.
Without identification testing, there is no objective check that the vial matches the label. Identification is the baseline — other tests are only meaningful if the compound was identified correctly first.
Net Content testing
How much peptide is actually in that vial?
The quantity of peptide in the vial, often as a percentage of label claim. 98% means 98% of the labeled amount.
A common approach is HPLC with quantitative comparison to a certified reference standard. The sample is separated on a column; the target peptide produces a chromatographic peak. Peak response is compared to a standard of known concentration to estimate peptide present relative to claim.
Peptides are often supplied as salts (TFA or acetate forms). The counterion has mass and is part of the solid. Label may state total mass including salt, while "net peptide content" refers to the active peptide mass. If your research relies on label claim for dosing, under/over-filling affects experimental planning.
Net Purity testing
What else is in the vial besides the peptide?
How much of the measured material is the target peptide versus everything else — related sequences, byproducts, fragments, and other impurities.
HPLC chromatogram is integrated for all peaks. Main peak is the target peptide; other peaks are impurities. Purity = main peak area ÷ sum of all peak areas. Some workflows use UV at 214nm to emphasize peptide bonds.
Solid-phase peptide synthesis builds chains stepwise; incomplete coupling can yield truncated sequences. Other impurities may include deletion sequences, oxidized residues, aggregates, or residual reagents. Lower purity means more non-target material — some impurities may be biologically active, others inert.
Endotoxins testing
How much bacterial endotoxin is present?
An endotoxin is a toxic component from the outer wall of Gram-negative bacteria — often lipopolysaccharide (LPS). The immune system responds strongly to LPS. Endotoxin can persist even after organisms are removed.
LAL is sensitive to LPS, reported in endotoxin units per mg or per mL (EU/mg, EU/mL). Some labs use rFC (recombinant Factor C) with different reagent sourcing but same biology.
A sample can be "sterile" (no growth in sterility test) and still contain endotoxin. That's why sterility and endotoxin are different COA lines. Sources include water systems, equipment biofilms, raw materials, and environmental contamination.
Sterility testing
Are there living microorganisms in the vial?
Looks for viable microorganisms — bacteria (aerobic and anaerobic), yeast, and mold — in the tested portion of the sample.
Direct inoculation: sample added to growth media and incubated under aerobic and anaerobic conditions. Membrane filtration: sample is filtered; the filter is transferred to media and incubated — useful when the matrix inhibits growth until diluted or removed.
Sterility is performed on a sample, not the entire batch. "No growth" means none was detected under the method and incubation period — not a guarantee for every unit in the lot. Most informative alongside controlled manufacturing and endotoxin data.
Heavy Metals testing
What trace elements came from synthesis or materials?
Tests for elemental contaminants — often lead, arsenic, cadmium, mercury, sometimes nickel, chromium, or catalyst residues (like palladium).
ICP-MS (inductively coupled plasma mass spectrometry): matrix is atomized/ionized in plasma; masses separated and quantified at very low levels (ppb or below).
Sources: reagents/solvents not controlled for trace metals, equipment leaching under acidic conditions, metal catalysts not fully cleared during purification, raw materials with trace metal backgrounds. A product can pass microbial tests yet fail elemental limits.
Lot Traceability testing
Can you match this specific vial to a specific test report?
A code identifying a defined production batch. Listed product, packaging, and COA should reference the same identifier.
Vendor assigns a lot/batch number to each production run. Same identifier appears on the vial, packaging, and COA for that batch.
Without traceability, a COA could be from any batch — including one tested months earlier with no relationship to what you actually received. Lot matching = real verification.
Third-Party Lab Testing testing
Who actually ran the tests?
Tests run by an independent lab with no financial relationship to the supplier, ideally ISO 17025 accredited.
Vendor sends product samples to an external lab. Lab issues a COA on their letterhead, with their certification info.
Vendor-issued "COAs" are not third-party verified. Independent lab COAs from ISO 17025 facilities are the gold standard.
Conformity testing
Are vials consistent with each other within a batch?
Checking multiple vials from the same lot for consistency — typically identification, net content, and net purity across multiple pulls.
Multiple data points for the same lot — either on an extended report or separate conformity summary — showing more than one vial tested for identity, content, and purity.
Filling and finishing can introduce vial-to-vial variation. A single COA cannot reveal uneven filling or localized contamination affecting only part of a batch.
Third-party testing labs
These laboratories appear at least once in our supplier testing data. Each summary paraphrases the lab's public website. PeptideSmart does not endorse any lab — refer to the lab's official site for authoritative information.
AFI
visit site →Analytical Formulations Lab. Confirm scope on their official site.
Chromate
visit site →Supplement analysis in USA, literature-based methods, results published via "Verify" portal.
Eagle Analytical
visit site →Analytical chemistry, microbiology testing, consulting, calibration, certification, and compliance services for FDA-regulated industries.
Ethos Analytics
visit site →ISO 17025 lab in Phoenix, AZ. Peptide purity/quantitation, nutraceutical testing, food/beverage, OTC, cosmetics, shelf-life/stability, Amazon compliance.
Eurofins
visit site →Global leader in bioanalytical, environmental, and pharmaceutical testing. Major peptide analytical services.
Freedom Diagnostics
visit site →High-precision purity testing for research-use-only peptides. Online COA lookup. RUO disclaimer enforced.
ILS Labs
visit site →ISO 17025 accredited (San Diego, CA). Peptide QC panels: HPLC purity, USP 85-style endotoxin testing, sterility screening, ICP-MS metals. QR-verified COAs. 3-5 day turnaround.
Janoshik
visit site →Chemical analysis for peptides, steroids, and pharmaceutical compounds. Digital reporting with account-based access. Industry-standard for peptide research COAs.
Kovera Labs
visit site →Compound testing and COA verification services.
MZ Biolabs
visit site →Specialty mass spectrometry testing for research, medical, and veterinary markets. Tucson, AZ operations.
Vanguard Laboratory
visit site →ISO/IEC 17025 certified. Peptide and research-chemical testing. HPLC purity, quantitation, endotoxin, sterility, ICP-MS metals, identity testing.
Quick reference
- Certificate of Analysis (COA)
- A document from a testing lab listing tests performed, methods, numerical results, and acceptance criteria for the sampled batch.
- Lot / Batch Identifier
- A code identifying a defined production batch. Product, packaging, and COA should all reference the same identifier for traceability.
- HPLC (High-Performance Liquid Chromatography)
- The primary analytical method for peptide purity and content measurement. Separates compounds on a column for quantitative analysis.
- LC-MS (Liquid Chromatography-Mass Spectrometry)
- Combines HPLC separation with mass spectrometry detection. Standard method for peptide identification.
- ISO 17025
- International standard for testing and calibration laboratories. Accreditation = high credibility for COAs.